Retrograde cutter with rotating blade

ABSTRACT

A cutting instrument having a body, a blade at a distal end of the body, and a mechanism for rotating the blade from a first to a second position. The instrument can be used in a method of retrograde drilling a hole in bone. The cutting instrument is provided with a mechanism (for example, a pin and a slot) that converts linear motion into rotational motion and locks the blade into position. The cutting blade is configured to engage the shaft of the instrument and to lock into the shaft. The cutting blade is articulated between at least a first “straight” position (for example, about parallel to the longitudinal axis of the instrument) when the instrument cuts in an antegrade manner, and at least a second “flip” position (for example, a non-parallel position relative to the longitudinal axis of the instrument) when the instrument cuts in a retrograde manner. The cutting blade may be provided with a suture passing notch. The cutter instrument may also include a button mechanism for controlling the linear movement.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.61/141,183 entitled “MECHANISM FOR CONVERTING LINEAR MOVEMENT INTOROTATIONAL MOVEMENT FOR SURGICAL INSTRUMENT,” filed on Dec. 29, 2008,the entire disclosure of which is incorporated by reference herein. Thisapplication is also a continuation-in-part of U.S. application Ser. No.12/114,599 (published as U.S. Publ. No. 2009/0275950 A1), filed May 2,2008, which claims priority to U.S. Provisional Application No.60/915,607, filed on May 2, 2007, the entire disclosures of which arehereby incorporated by reference.

FIELD OF THE INVENTION

The present invention relates to a mechanism for converting linearmovement into rotational movement for a surgical instrument, such as aflip retrograde cutting instrument.

BACKGROUND OF THE INVENTION

During arthroscopic surgery, a small incision is made in the skincovering the arthroscopic site or joint, and a cannula is inserted inthe incision to provide a pathway for surgical instruments to be placedin the joint and manipulated through arthroscopic visualization.Surgical instruments inserted through cannulas must be long andthin—this presents limitations on instruments for cutting tissue, as thediameter of the cannula ordinarily limits the width of the cuttingimplement.

Retrograde drilling of sockets and tunnels for ACL reconstruction usinga flip cutter is known and described, for example, in U.S. applicationSer. No. 12/114,599, filed on May 2, 2008, published as U.S. Publ. No.2009/0275950 A1 and EP 1987786, the disclosures of which areincorporated by reference herein. This prior published applicationdescribes a flip retrograde cutter having a blade, preferably a flipblade, that is configured to articulate between at least a first“straight” position, for example, substantially parallel to alongitudinal axis of the flip retrograde cutter, and at least a second“flip” position, for example, a non-parallel position relative to thelongitudinal axis of the flip retrograde cutter. Using such a flipretrograde cutter, a recipient site socket can be created from theinside out, i.e., using a retrograde technique, with minimal incisionsof distal cortices and reduced intraarticular bone fragmentation oftunnel rims.

The flip retrograde cutter described above may be employed in aretrograde manner to form a recipient socket (to accommodate anosteochondral transplant, or to allow retrograde fixation of a graftwithin two sockets, for example). Formation of the recipient socketbegins by inserting the flip retrograde cutter in the “straight”configuration into the joint space, preferably from the outside in,through a small diameter tunnel. A locking tube of the instrument isthen retracted so that the blade can be articulated into the “flip”configuration, i.e., into a position other than the “straight” positionand preferably at about 90 degrees to the longitudinal axis of theinstrument. The device is locked in the “flip” position by tighteningthe locking tube. A socket is created by conducting a drillingoperation, i.e., by rotating the instrument, while the device is pulledoutwardly.

A need exists for a mechanism that facilitates flipping of the blade inthe above-described instrument by converting linear movement of theshaft into rotational movement of the cutter blade (without the need tomanually flip the cutter blade into position within the joint).

SUMMARY OF THE INVENTION

The present invention provides a cutting instrument that is designed toautomatically convert linear movement of the shaft of the instrumentinto a rotational movement of the cutter tip (for example, a blade) ofthe instrument. The flip cutter instrument is provided with a mechanism(for example, a pin and a slot) that converts linear motion intorotational motion and locks the blade into position. The cutting bladeis configured to engage the shaft of the instrument and to lock into theshaft. The cutting blade is articulated between at least a first“straight” position (for example, about parallel to the longitudinalaxis of the instrument) when the instrument cuts in an antegrade manner,and at least a second “flip” position (for example, a non-parallelposition relative to the longitudinal axis of the instrument) when theinstrument cuts in a retrograde manner. The cutting blade may beprovided with a suture passing notch. The cutter instrument may alsoinclude a button mechanism for controlling the linear movement.

The cutter of the present invention may be employed in an antegrademanner, or in a retrograde manner, or both in an antegrade andretrograde manner, to form a recipient socket (to accommodate anosteochondral transplant, or to allow retrograde fixation of a graftwithin two sockets, for example).

These and other features and advantages of the invention will be moreapparent from the following detailed description that is provided inconnection with the accompanying drawings and illustrated exemplaryembodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a schematic cross-sectional view of a flip cutteraccording to a first embodiment of the present invention, and with theblade in the “straight” configuration.

FIGS. 2 and 3 illustrate the flip cutter of FIG. 1, with the blade insequential “flip” configurations.

FIG. 4 illustrates the flip cutter of FIG. 1, with the blade in thelocked “flip” configuration.

FIG. 5 illustrates a perspective view of a flip cutter according to asecond embodiment of the present invention, and with the blade in the“flip” configuration.

FIG. 6 illustrates a side view of the flip cutter of FIG. 5, with theblade in the locked “flip” configuration.

FIG. 7 illustrates a top view of the flip cutter of FIG. 5, with theblade in the locked “flip” configuration.

FIGS. 8 and 9 illustrate side views of the push button mechanism of theflip cutter of FIG. 5.

FIG. 10 schematically illustrates the formation of a socket with theflip cutter of the present invention.

DETAILED DESCRIPTION

The following description is provided to enable any person skilled inthe art to make and use the invention and sets forth the best modescontemplated by the inventors of carrying out their invention. Variousmodifications, however, will remain readily apparent to those skilled inthe art.

The present invention provides a flip cutter instrument that is designedto automatically convert linear movement of the shaft of the instrumentinto a rotational movement of the cutter tip (blade) of the instrument.The flip cutter instrument is provided with a mechanism (such as a pinand a slot, for example) that converts linear motion into rotationalmotion and locks the blade into position. The cutting blade isconfigured to engage the shaft of the instrument and to lock into theshaft. The blade is articulated between at least a first “straight”position (for example, about parallel to the longitudinal axis of theinstrument) and at least a second “flip” position (for example, anon-parallel position relative to the longitudinal axis of theinstrument). The cutting blade may be provided with a suture passingnotch.

The instrument may function in an antegrade or retrograde manner (whenin the “flip” mode), or both in an antegrade or retrograde manner, toform a recipient socket (to accommodate an osteochondral transplant, orto allow retrograde fixation of a graft within two sockets, forexample).

As described in more detail below, formation of the recipient socketbegins by inserting an outer tube and an inner tube (i.e., a shaft) ofthe instrument into the joint space, preferably from the outside in,through a small diameter tunnel. A cutting blade is attached to both theouter tube and the inner tube of the instrument. The cutting blade maybe provided with a suture passing notch in the blade. Once the shaftundergoes linear movement or linear motion, a mechanism (a pin and slotmechanism, for example) converts the linear movement of the shaft (inrelation to the tube) into rotational movement of the cutting blade. Thepin and slot mechanism also locks the blade on the outer tube when theblade is in the “flip” position. A socket is created by conducting adrilling operation while the device is pulled in a retrograde manner, asdescribed, for example, in U.S. Patent Application Publ. No.2008/0306483, the disclosure of which is incorporated by reference inits entirety herewith. Other methods of retrograde drilling known in theart may also be used to create the socket.

Referring now to the drawings, where like elements are designated bylike reference numerals, FIGS. 1-9 illustrate various views of flipcutter 100, 200 of the present invention and at various stages ofconverting linear motion to rotational motion. FIG. 10 illustrates aschematic view of the retrograde flip cutter 100 of FIGS. 1-4 providedin the vicinity of a knee, where ACL reconstruction is conductedaccording to the present invention. The flip cutter 100, 200 creates arecipient site socket from the inside out, i.e., using a retrogradetechnique, with minimal incisions of distal cortices and reducedintraarticular bone fragmentation of tunnel rims.

FIGS. 1-4 illustrate a first embodiment of flip cutter 100 of thepresent invention while FIGS. 5-9 illustrate a second embodiment of flipcutter 200 of the present invention (provided with a push buttonmechanism for deployment, and also with a suture passing notch in thecutting blade). As illustrated in FIGS. 1-4, flip cutter 100 includes acannulated elongated outer tube 10 having a distal end 12 and a proximalend (not shown). Distal end 12 is provided (at its most distal part)with a mechanism 15 that is configured to engage a correspondingstructure of blade 30 to be attached and securely engaged to the outertube 10.

The outer tube 10 of the retrograde cutter 100 houses an inner tube orshaft 20 with a diameter smaller than that of the outer tube 10. Blade30 is provided at distal end 12 of the outer tube 10 and is connected toboth the outer tube 10 and the inner shaft 20 by mechanism 15. In anexemplary embodiment, and as shown in FIG. 1, blade 30 is pinned to theouter tube 10 and is also pinned to the shaft 20. Outer tube 10 isprovided with a cutout 14 that allows movement of blade 15 within thecutout and relative to the outer tube 10. Blade 30 of the cutter 100 mayhave a body provided in various shapes and geometries, and may includecutting edges or surfaces also of various configurations.

In an exemplary embodiment, mechanism 15 comprises a pin and a slot thatallow conversion of the linear movement of the shaft of the instrumentinto rotational movement of the cutter tip (cutting blade) of theinstrument. For example, as shown in FIGS. 1-4, mechanism 15 may includea first pin hole 16 a (or first pin slot 16 a) with a first pin 16 bconnecting blade 30 to tube 10, where the first pin hole 16 a permitsonly rotational movement, and a second pin hole 17 a (or second pin slot17 a) with a second pin 17 b connecting blade 30 to shaft 20, where thesecond pin hole 17 a is a slot permitting rotational and slidingmovement of blade 30 relative to the second pin 17 b. As shown in FIGS.2 and 3, when tube 10 is advanced in a linear direction parallel to thelongitudinal axis of the flip cutter 100, the first pin pushes one sideof the proximal end of blade 30 in the linear direction, while thesecond pin is permitted to slide in the slot of the second pin hole,thus permitting rotation of blade 30.

In use, blade 30 is attached to both the outer tube 10 and the innertube 20 by engaging mechanism 15. The outer tube 10 and the inner tube20, with the blade attached and locked in the “straight” configuration,are inserted into a joint from the distal side, until they are visiblein the joint.

Once the instrument reaches the joint, a linear motion may be carriedout so that one of the tubes 10, 20 advances relative to the other ofthe tubes 10, 20 (for example, the outer tube 10 advances relative tothe inner shaft 20) by sequential distances d₁ (FIG. 2), d₂ (FIG. 3) andd₃ (FIG. 4). At the point where outer tube 10 travels distance d₃ (FIG.4) relative to the inner tube 20 (or when the inner tube 20 travelsdistance d₃ relative to the outer tube 10), the blade 30 is in a lockedand “flip” position, i.e., about perpendicular to the longitudinal axisof the instrument. In this manner, movement of the outer tube relativeto the inner shaft (i.e., while traveling a distance between about 0 toabout d₃) converts the linear motion of the tube into a rotationalmotion of blade 30.

Although FIGS. 1-4 illustrate blade 30 being articulated to the secondposition upon movement of tube 10 in a distal direction, it should beunderstood that other embodiments could include blade 30 beingarticulated to the second position upon movement of either shaft 20 ortube 10 in a proximal direction. In addition, although FIGS. 1-4illustrate outer tube 10 being moved linearly, it should be understoodthat the articulation of blade 30 to the second position occursaccording to relational movement of the outer and inner tubes, and thusother embodiments could include inner tube 20 being moved in a linear(distal or proximal) direction.

Once blade 30 is locked onto cutting instrument 100 (FIG. 4), a cuttingor drilling operation, for example, a retrograde drilling step, may besubsequently carried, as known in the art. According to an exemplaryembodiment only, the cutter of the present invention may be employed ina retrograde manner to form a recipient socket (at the location of anosteochondral lesion developed on the head of the tibia, for example, orto accommodate retrograde fixation of a graft within two sockets). Forexample, and as detailed below, FIG. 10 illustrates cutter 100 of FIGS.1-4 in the vicinity of femur 91 and tibia 93 of knee 99.

FIGS. 5-9 illustrate flip cutter 200 according to another embodiment ofthe present invention. Flip cutter 200 is similar to the flip cutter 100of FIGS. 1-4, but differs in that the handle of cutter 200 includes apush button mechanism 250 (illustrated in detail in FIGS. 8 and 9) fordeployment of blade 230. Flip cutter 200 also differs from the flipcutter 100 of FIGS. 1-4 in that blade 230 is provided with a suturepassing notch 233 (illustrated in more detail in FIGS. 6 and 7). As inthe previously-described embodiment, outer tube 210 of the cutter 200 isprovided at its most distal end with a cutout 214 that allows blade 230to pivot from an angle of about zero degrees relative to a longitudinalaxis of the tube 210 to an angle of about ninety degrees relative to thelongitudinal axis of the tube 210.

Push button mechanism 250 may be configured to advance an inner or outertube of a body 210 of flip cutter 200 (i.e., similar to shaft 20 andtube 10 of flip cutter 100 in FIGS. 1-4) in a linear direction (forexample, a distal direction) to rotate and lock blade 230 in a “flip”position using a mechanism similar to the configuration described abovewith regard to flip cutter 100. In another exemplary embodiment, pushbutton mechanism 250 may lock cutter 200 and prevent relational movementof the inner and outer tubes until push button mechanism 250 is engaged.

An exemplary method of ACL reconstruction may be performed according toan embodiment of the present invention by employing cutter 100 (FIGS.1-4) or cutter 200 (FIGS. 5-9) to form at least one of a femoral andtibial socket. For example, with cutter 100 oriented as shown in FIG.10, a tibial socket or tunnel is formed within tibia 93 in a retrogrademanner.

The present invention may be used to form various sockets or tunnels toallow fixation of a graft (for example, a semitendonosus allograft) orto allow replacement of osteochondral cores or implants in a retrogrademanner, to obviate inserting harvesters into the joint. For example,cutting instrument 100, 200 of the present invention may be employed forthe formation of sockets during an “All-Inside ACL RetroConstruction”for ligament repair, developed by Arthrex, Inc. of Naples, Fla. (anddisclosed in U.S. Patent Application Publ. No. 2009/0275950,incorporated by reference above), which comprises, for example, thesteps of: (i) drilling at least one of a femoral and tibial tunnel orsocket using the cutting instrument 100, 200 of FIGS. 1-9; (ii)providing a graft (soft tissue graft or BTB graft) in the vicinity ofthe sockets; and (iii) securing the graft within the femoral and tibialtunnels (sockets).

According to yet another embodiment, an exemplary method of ACLretrograde reconstruction of the present invention comprises, forexample, the steps of: (i) drilling a femoral socket; (ii) drilling atibial tunnel or socket using a retrodrill technique employing thecutting instrument 100, 200 of FIGS. 1-9; (iii) providing a graft (softtissue graft or BTB graft) in the vicinity of the sockets; (iv) securingthe graft (soft tissue graft or BTB graft) to a continuous loop/buttonconstruct comprising a button with an oblong configuration and providedwith an inside eyelet that allows the passage of the continuous loop,preferably a suture loop; (v) passing the graft with the button throughthe femoral tunnel; (vi) securing the button to the femoral cortex oncethe button exits the femoral socket; and (vii) securing the graft in thetibial tunnel or socket.

Although the present invention has been described in connection withpreferred embodiments, many modifications and variations will becomeapparent to those skilled in the art. While preferred embodiments of theinvention have been described and illustrated above, it should beunderstood that these are exemplary of the invention and are not to beconsidered as limiting.

1. A retrograde cutter comprising: an elongated body having a distalend, a proximal end, and a longitudinal axis, said body furthercomprising an outer tube and an inner tube housed by said outer tube; ablade at said distal end of said body, wherein said blade is configuredto rotate from a first position generally aligned with said longitudinalto a second position which is not aligned with said longitudinal axis;and a mechanism connecting said blade to distal ends of said outer andinner tubes, wherein said mechanism is configured to rotate said bladeto said second position upon linear movement of one of said inner andouter tubes in relation to the other of said inner and outer tubes. 2.The retrograde cutter of claim 1, said mechanism further comprising: afirst pin connecting said blade to said outer tube; and a second pinconnecting said blade to said inner tube.
 3. The retrograde cutter ofclaim 2, said blade further comprising a second pin hole for connectingsaid blade to said second pin, said second pin hole permittingrotational and sliding movement of said blade relative to said secondpin.
 4. The retrograde cutter of claim 3, said blade further comprisinga first pin hole for connecting said blade to said first pin, said firstpin hole permitting rotational movement of said blade relative to saidfirst pin.
 5. The retrograde cutter of claim 1, wherein said mechanismis configured to rotate said blade to said second position upon linearmovement of said outer tube in a distal direction in relation to saidinner tube.
 6. The retrograde cutter of claim 5, wherein said mechanismis configured to lock said blade in said second position upon reachingsaid second position.
 7. The retrograde cutter of claim 5, said innerand outer tubes further comprising threads for locking said inner andouter tubes to prevent relational linear movement.
 8. The retrogradecutter of claim 1, wherein said second position is approximatelyperpendicular to said longitudinal axis of said body.
 9. The retrogradecutter of claim 1, wherein, in said second position, said blade forms anacute angle with said body.
 10. The retrograde cutter of claim 1,wherein, in said second position, said blade forms an obtuse angle withsaid body.
 11. The retrograde cutter of claim 1, further comprising abutton mechanism at said proximal end of said body, wherein said buttonis configured to control said relational linear movement of said inneror outer tube.
 12. The retrograde cutter of claim 11, wherein saidbutton is configured to prevent relational movement of the inner andouter tubes until said button mechanism is engaged.
 13. The retrogradecutter of claim 11, further comprising a handle on said proximal end ofsaid body, wherein said button is on said handle.
 14. The retrogradecutter of claim 1, said blade further comprising a notch for holding asuture material.
 15. The retrograde cutter of claim 1, wherein saidblade is configured to provide retrograde drilling when locked in saidsecond position.
 16. A method of retrograde drilling comprising:providing a retrograde cutter including an outer tube and an inner tubehoused by said outer tube, a blade at distal ends of said outer andinner tubes in a first position generally aligned with longitudinal axisof said retrograde cutter; and a mechanism connecting said blade to saiddistal ends of said outer and inner tubes; inserting said blade into atarget area; advancing one of said inner and outer tubes in relation tothe other of said inner and outer tubes in a direction parallel to saidlongitudinal axis, such that said mechanism articulates said blade fromsaid first position to a second position which is not aligned with saidlongitudinal axis; and drilling a socket in a retrograde manner usingsaid blade.
 17. The method of claim 16, wherein said blade isarticulated to an angle within a range of about 10° to about 170° tosaid longitudinal axis in said second position.
 18. The method of claim17, said step of advancing one of said inner and outer tubes furthercomprising advancing said outer tube in relation to said inner tubeuntil said blade reaches said second position.
 19. The method of claim18, wherein said angle is approximately 90°.
 20. The method of claim 18,wherein said mechanism comprises a first pin connecting said blade tosaid outer tube and a second pin connecting said blade to said innertube, and said blade comprises a first pin hole for connecting saidblade to said first pin and a second pin hole for connecting said bladeto said second pin, said step of advancing further comprising movingsaid blade rotationally about said first pin and rotationally andslidingly about said second pin such that said blade rotates from saidfirst position to said second position.
 21. The method of claim 16, saidstep of inserting said blade into said target area comprising advancingsaid retrograde cutter through a cannula in a distal direction such thatsaid blade is located distally beyond a joint.
 22. The method of claim21, said step of drilling further comprising rotating said retrogradecutter while pulling said retrograde cutter in a proximal direction. 23.The method of claim 16, said retrograde cutter further comprising abutton mechanism at said proximal end of said inner and outer tubes,wherein said step of advancing said outer tube in relation to said innertube comprises engaging said button to advance one of said inner andouter tubes in relation to the other of said inner and outer tubes. 24.The method of claim 16, wherein said blade comprises a notch for holdinga suture material, said step of inserting said blade into a target areafurther comprising passing a suture held in said notch into said targetarea.